Which change in blood pressure during position changes defines orthostatic hypotension?

• A. A A decrease of 20 mm Hg in systolic pressure
• B. B An increase of 5 mm Hg in diastolic pressure
• C. C A decrease of 20 mm Hg in diastolic pressure
• D. D A decrease of 15 mm Hg in systolic pressure

Answer: (A)

Orthostatic hypotension is defined by a clinically significant drop in blood pressure when moving to an upright position, due to insufficient compensatory responses. The key measurement is a fall in systolic blood pressure by at least 20 mm Hg within about 3 minutes of standing (or a drop of diastolic pressure by about 10 mm Hg). The option describing a decrease of 20 mm Hg in systolic pressure matches this threshold, making it the best choice. This change reflects the body not maintaining adequate cerebral perfusion after position change, which can cause lightheadedness or faintness. The other options don’t represent the characteristic pressure drop associated with orthostatic hypotension.